Vehicle having an electrical machine optionally coupling with a transmission input shaft or output shaft

ABSTRACT

A vehicle having a transmission for transmitting a torque from a drive machine to drive wheels, with the transmission having a transmission output shaft and a transmission input shaft, in which the torque can be transmitted from the drive machine to the transmission output shaft, and having an electrical machine which has a rotor and a stator, with means being provided in order to connect the electric-motor torque of the electrical machine optionally to the transmission input shaft or to the transmission output shaft.

BACKGROUND AND SUMMARY OF THE INVENTION

The invention relates to a vehicle having a transmission fortransmitting a torque from a drive machine to drive wheels, with thetransmission having a transmission output shaft and a transmission inputshaft in which the torque can be transmitted from the drive machine tothe transmission output shaft, and having an electrical machine whichhas a rotor and a stator.

A vehicle having a starter/generator system for starting an internalcombustion engine is known from DE 198 49 051 C1. In this case, anelectrical machine is arranged between an internal combustion engine anda transmission. One problem is that the starter/generator cannot be usedto drive the vehicle. Normally, two electrical machines are providedwhen both starter/generator functions and hybrid functions are intendedto be provided in the vehicle.

The invention is based on the object of specifying a vehicle which hasan electrical machine which can be used both as a starter/generator andas a hybrid drive.

This object is achieved by a vehicle having a transmission fortransmitting a torque from a drive machine to drive wheels, with thetransmission having a transmission output shaft and a transmission inputshaft in which the torque can be transmitted from the drive machine tothe transmission output shaft, and having an electrical machine whichhas a rotor and a stator. Mechanisms are provided in order to connectthe electric-motor torque of the first electrical machine optionally tothe transmission input shaft or to the transmission output shaft.

According to the invention, the vehicle has means in order to connectthe electric-motor torque of an electrical machine optionally to thetransmission input shaft or to the transmission output shaft. The torqueis preferably transmitted with different transmission ratios to thetransmission input shaft and to the transmission output shaft. Theadvantage is that only a single electrical machine is required forstarter/generator and hybrid functions. The machine can be designed fordifferent requirements by means of transmission ratios which can bechosen freely. In addition to the known advantages of a parallel hybrid,a starter/generator function is also provided in the vehicle accordingto the invention.

It is self-evident that the features mentioned above and which are alsoexplained in the following text can be used not only in the respectivelystated combination but also in other combinations or on their own,without having to depart from the scope of the present invention.

Further advantages and refinements of the invention will become evidentfrom the other claims and from the description.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is described in more detail in the following text withreference to a drawing, in which the figures show:

FIG. 1 shows an outline illustration of one preferred arrangement with amanual transmission;

FIG. 2 shows an outline illustration of an alternative arrangement tothat in FIG. 1;

FIG. 3 shows a partial longitudinal section through a manualtransmission as shown in FIG. 2; and

FIG. 4 shows an outline illustration of an alternative arrangement tothat shown in FIG. 2 with a second electrical machine.

DETAILED DESCRIPTION OF THE DRAWINGS

The invention will be explained in the following text with reference toan arrangement having a manual transmission. However, the invention canalso be used in vehicles having automatic transmissions.

FIG. 1 shows a detail from the drive train of a vehicle according to theinvention having a transmission 2. For the sake of clarity, theillustration shows an additional shaft in the transmission, stressed inan idealized manner such that the illustration acts like a side view.The additional shaft is folded downwards with respect to the actualarrangement.

The manual transmission 2 is provided to transmit a torque from a drivemachine 1, such as an internal combustion engine, to drive wheels (notshown). The transmission 2 has a transmission output shaft 5 and atransmission input shaft 4. The torque from the drive machine 1 istransmitted to the transmission input shaft 4, and from there to thetransmission output shaft 5. A layshaft 6 is provided for this purposeand is provided, in the normal manner, with gearwheels, whilegear-changing and synchronization means are provided, in order to selectbetween different gearwheels with different transmission ratios, in thenormal manner. The torque can thus be transmitted from the drive machine1 with different transmission ratios via the transmission 2 to the drivewheels.

Furthermore, an electrical machine 3 is arranged between the drivemachine 1 and the transmission 2, and has a rotor 32 and a stator 31.The electrical machine 3 is preferably in the form of an internal rotormachine. However, an external rotor arrangement may also be used.

Means 35, 33, 34, 7, 8, 9, 10, 20 are provided in order to connect anelectric-motor torque from the electrical machine 3 optionally either tothe transmission input shaft 4 or to the transmission output shaft 5.The electrical machine 3 is operated as a starter/generator when itstorque is transmitted to the transmission input shaft 4.

If the torque is transmitted to the transmission output shaft 5, theelectrical machine 3 acts as a further drive machine, which can drivethe vehicle instead of or in addition to the drive machine 1.

The particular advantage is that, in consequence, the same electricalmachine can be used for two different purposes. Only one electricalmachine is thus required in order to provide a starter/generator modefor a vehicle and to drive it as a parallel hybrid. The possible methodof operation of the electrical machine 3 depends essentially only on itsphysical length.

The rotor 32 of the electrical machine 3 is held by a rotor holder 35.The rotor 32 coaxially surrounds the rotor holder 35, which surroundsthe transmission input shaft 4. The rotor is connected in a rotationallyfixed manner to a third gearwheel 33. This is operatively connected to afourth gearwheel 34, which is connected in a rotationally fixed mannerto an additional shaft 7. When the rotor 32 rotates, the third gearwheel33 rotates with it and engages with the fourth gearwheel 34. Inconsequence, the additional intermediate shaft 7 is driven.

The additional intermediate shaft 7 has a first gearwheel 10 and asecond gearwheel 20. The layshaft 6 has gearwheels 11, 21 associated ina corresponding manner with these gearwheels 10, 20. When the firstgearwheel 10 on the additional intermediate shaft 7 interacts with thefirst gearwheel 11 on the layshaft 6, the torque from the electricalmachine 3 is transmitted to the transmission input shaft 4. The rotatingelectrical machine 3 can thus overcome the breakaway torque of the drivemachine 1, when the clutch 41 is engaged, thus starting this drivemachine 1 from rest.

When the second gearwheel 20 on the additional intermediate shaft 7interacts with the second gearwheel 21 on the layshaft 6, the torque ofthe electrical machine 3 is transmitted to the transmission output shaft5, and the electrical machine 3 can be used to drive the vehicle. Thiscorresponds to a parallel hybrid. In this case, it is advantageous thatthe electrical machines 3 that are used can be designed advantageouslyfor different requirements since the transmission ratios of thegearwheels 10, 11, 20, 21 can be selected freely.

Thus, for example, a transmission ratio i of i=2:1 can be selected forthe first gearwheels 10, 11 during starting, and a transmission ratio ofi=1:1 can be selected for the second gearwheels 20, 21 for driving. Thisresults in a considerable improvement in the efficiency of theelectrical machine 3.

In order to transmit the electric-motor torque of the electrical machine3 from the additional intermediate shaft 7 to the transmission inputshaft 4, the first gearwheel 10 is operatively connected to the firstgearwheel 11 on the layshaft 6, by a first gear-changing andsynchronization means 8 synchronizing the two gearwheels 10, 11, andoperatively connecting them.

In order to transmit the electric-motor torque of the electrical machine3 from the additional intermediate shaft 7 to the transmission outputshaft 4, the second gearwheel 20 is operatively connected to the secondgearwheel 21 on the layshaft 6, by a second gear-changing andsynchronization means 9 synchronizing the two gearwheels 20, 21 andoperatively connecting them.

In the case of an automatic transmission, preferably with an automaticgear-changing and starting clutch 41, the preferred solution also allowsgear changing under load.

Instead of a manual transmission as the transmission 2, an automatictransmission can also be used, in which case the torque of theelectrical machine 3 can be switched backwards and forwards between thetransmission input shaft 3 and the transmission output shaft 5 by meansof epicyclic gearing.

One advantageous factor is that vehicles with transmissions normallyintrinsically have virtually sufficient physical space to provide, forexample, an additional intermediate shaft 7 and/or an electrical machine3. If necessary, the transmission 2 or the transmission bellhousing 40must be lengthened somewhat, depending on the design of the electricalmachine 3. The solution according to the invention allows very compactintegration of an electrical machine in the vehicle according to theinvention, without having to provide any complex structures.

The electrical machine 3 is preferably arranged between the drive engine1 and the transmission bellhousing 40. The electrical machine 3 can alsobe arranged inside the transmission bellhousing 40. It is also possibleto provide the transmission 2 between the drive machine 1 and theelectrical machine 3. In consequence, an advantageous physical area canbe used for different electrical machines.

FIGS. 2 and 3 as well as FIG. 4 show alternative arrangements to thoseshown in FIG. 1. Components which essentially remain the same are inprinciple still annotated with the same reference symbols. Furthermore,reference can be made to the description of the exemplary embodimentrelating to FIG. 1 for features and functions which remain the same.

The following description is restricted essentially to the differencesfrom the exemplary embodiment in FIG. 1.

In the arrangement shown in FIG. 2, a gear-changing and synchronizationmeans 50 and an electrical machine 3 are arranged such that theyintersect in the axial direction, or the gear-changing andsynchronization means 50 are arranged radially inside a rotor 32 of theelectrical machine 3. The utilization of the space inside the rotor 32results in a particularly compact design.

The electrical machine 3 and the gear-changing and synchronization means50 surround a transmission input shaft 4. The electrical machine 3 canbe coupled directly to the transmission input shaft 4 via thegear-changing and synchronization means 50, to be precise by pushing asliding collar 51 of the gear-changing and synchronization means 50 overan actuator, which is not shown in any more detail, in the direction ofa gear-changing clutch 41 for the transmission 2. This results in ashort connection, via a small number of different components, betweenthe drive machine 1 and the electrical machine 3 and hence in highefficiency, particularly when the electrical machine 3 is being used tostart the drive machine 1.

The electrical machine 3 can furthermore be coupled via thegear-changing and synchronization means 50 and via a pair of gearwheels52 to an additional intermediate shaft 7. The pair of gearwheels 52 hasa loose wheel 55 mounted on a transmission flange 62 and a fixed wheel56 mounted on an additional intermediate shaft 7 (see FIGS. 2 and 3,FIG. 2 shows the arrangement without the transmission flange 62).

The intermediate shaft 7 is connected via a fixed wheel 57, which ismounted on the intermediate shaft 7, to a fixed wheel 58 which ismounted on a transmission output shaft 5.

In order to couple the electrical machine 3 to the intermediate shaft 7,and hence to the transmission output shaft 5, the sliding collar 51 ofthe gear-changing and synchronization means 50 is pushed over theactuator, in the direction facing away from the gear-changing clutch 41.The two possible selection positions of the gear-changing andsynchronization means 50 thus mean that a gear-changing andsynchronization means, and hence space and weight, can be saved incomparison to the arrangement shown in FIG. 1.

In order to start the drive machine 1 and to operate the generator whenthe vehicle is stationary, and for generator operation and recuperationoperation, that is to say to convert kinetic energy to electrical energyduring braking, the electrical machine 3 is coupled via thegear-changing and synchronization means 50 directly to the transmissioninput shaft 4 when travelling at speeds above 140 km/h. For generatoroperation and for recuperation operation when travelling at speeds below140 km/h and in order to drive the vehicle electrically, to assist thedrive machine 1 and/or for boosting and load changing, that is to saychanging over to drive the vehicle electrically during a gear-changingprocess, the electrical machine 1 is connected to the intermediate shaft7 via the gear-changing and synchronization means 50 and via the pair ofgearwheels 52.

The loose wheel 55, a clutch body 59 facing away from the gear-changingclutch 41, a synchronization ring 60 associated with the clutch body 59and a base body 61 of the gear-changing and synchronization means 50 aremounted on the transmission flange 62 (FIGS. 2 and 3). The transmissionflange 62 is screwed to a transmission housing 63 on the side facingaway from the gear-changing clutch 41. The transmission flange 62 hascutouts 64 in its external diameter on the side facing away from thegear-changing clutch 41, in order to avoid any influence from thephysical shape of the transmission housing 63 and from the space of theintermediate shaft 7 and of a layshaft 6. The pair of gearwheels 52 andthe electrical machine 3 are arranged such that they intersect in theaxial direction, or the pair of gearwheels 52 is arranged radiallyinside a coil core 69 of the electrical machine 3, thus resulting in acompact design.

The transmission flange 62 is designed to have a roller running surfacein an accommodation area for the loose wheel 55 and the base body 61.Furthermore, the insides of the components 55, 61 which are on bearingsare designed with roller running surfaces. The loose wheel 55 hashelical teeth and produces axial forces during operation. If axialforces occur in the direction facing away from the gear-changing clutch41 during operation, these are supported on the transmission flange 62,to be precise via very finely machined abutting surfaces. If axialforces in the direction of the gear-changing clutch 41 occur duringoperation, these are supported via the base body 61, which has needlebearings, on an abutting sleeve 65 screwed into the transmission flange62. The abutting sleeve 65 has an external thread which is screwed intoan internal thread in the transmission flange 62, which is in the formof a sleeve. The abutting surfaces are lubricated with oil, which isapplied to the abutting surfaces by means of a lubricant supply.

If the abutting sleeve 65 is screwed into the transmission flange 62during assembly, the sliding collar 51, a clutch body 66 facing thegear-changing clutch 41 and a synchronization ring 82 can be fitted. Theclutch body 66 has an internal tooth system 67 which engages in anexternal tooth system 68 on the transmission input shaft 4, and isconnected to it in a rotationally fixed manner.

A stator 31 and cooling rings 70 for the electrical machine 3 arepressed into the transmission housing 63 with a force fit. The rotor 32of the electrical machine 3 is mounted on a rotor support 71, via whichrotor laminates of the rotor 32 are braced via extensions at the side. Alocking ring 72 is arranged in an annular groove on the innercircumference of the rotor support 71, which is in the form of a sleeve,for axial positioning of the rotor support 71. The rotor support 71 ismounted in an O-arrangement on a retaining flange 75 via twoangled-contact ball bearings 73, 74, which are arranged in a row and areslightly prestressed, thus providing a stiff bearing for the rotor 31with a small bearing width. The locking ring 72 is clamped in betweenouter rings of the angled-contact ball bearings 73, 74, by which meansit, the rotor support 71 and the rotor 31 are fixed in the axialdirection. The lubricant supply to the abutting surfaces of thegear-changing and synchronization means 50 ensures an adequate supply tothe bearing for the rotor 31 and for the rotor support 71.

The retaining flange 75 is screwed on its outer circumference to thetransmission housing 63 by means of screws which are not illustrated inany more detail, and forms a separating wall between the transmission 2and the gear-changing clutch 41. Sealing for the oil-lubricatedtransmission space from the clutch space is ensured by a radial shaftsealing ring 78. The radial shaft sealing ring 78 is integrated in anabutting disc 79, thus resulting in an axially compact design. Theabutting disc 79 is furthermore used to prestress the angled-contactball bearings 73, 74. The abutting disc 79 is screwed into the retainingflange 75, to be precise from the outside, while a central disengagingdevice 80 is being fitted. Axial forces, when the central disengagingdevice 80 is in the selection state, in the direction of thetransmission 2 are supported via the retaining flange 75 and via theabutting disc 79, the clutch body 66, the base body 61, the loose wheel55 and via the transmission flange 62 on the transmission housing 63.

A hollow ring 76 with an internal tooth system is pressed in aforce-fitting manner onto the internal circumference of the rotorsupport 71, and engages with an external tooth system on a ring 77 whichis integrally formed on the sliding collar 51.

A second electrical machine 53 is provided, in addition to a firstelectrical machine 3, in the arrangement shown in FIG. 4, and its rotor81 is connected in a rotationally fixed manner to an output shaft 54, orto a crankshaft, of a drive machine 1, and is used as a flywheel massfor the drive machine 1.

The two electrical machines 3, 53 are separated by a torsionaloscillation damper, which is not shown in any more detail, and by agear-changing clutch 41.

The second electrical machine 53 allows the drive machine 1 to bestarted in a particularly short time while the vehicle is being drivenvia the first electrical machine 3, without any need to switch over thefirst electrical machine 3. The drive machine 1 can be switched offwhile the vehicle is being driven by the first electrical machine 3,although the maximum power is nevertheless available on short notice.Furthermore, the second electrical machine 53 can be used to drive thevehicle, for boosting, for recuperation and for generator operation. Thesecond electrical machine 53 and the gear-changing clutch 41 as well asthe torsional oscillation damper intersect in the axial direction, orthe gear-changing clutch 41 and the torsional oscillation damper arearranged radially inside the second electrical machine 53, thusresulting in an axially compact design.

What is claimed is:
 1. Vehicle, comprising: a transmission fortransmitting a torque from a drive machine to drive wheels, saidtransmission having a transmission output shaft and a transmission inputshaft, in which the torque can be transmitted from the drive machine tothe transmission output shaft; an electrical machine which has a rotorand a stator; and means for connecting an electric-motor torque of theelectrical machine optionally to the transmission input shaft or to thetransmission output shaft, wherein the transmission is a manualtransmission, and wherein said means comprises a layshaft of the manualtransmission and an additional intermediate shaft in the manualtransmission interacting with the layshaft and, further wherein at leastone first or second gearwheel on the layshaft is operatively connectedto at least one associated first or second gearwheel on the additionalintermediate shaft.
 2. Vehicle according to claim 1, wherein theadditional intermediate shaft is connected to the rotor of theelectrical machine and can be driven by the rotor.
 3. Vehicle accordingto claim 1, wherein said means further comprises a first gear-changingand synchronzation device associated with the additional intermediateshaft which synchronizes and operatively connects the first gearwheel onthe intermediate shaft to the first gearwheel on the layshaft in orderto transmit the electric-motor torque of the electrical machine from theadditional intermediate shaft to the transmission input shaft. 4.Vehicle according to claim 3, wherein said means further comprises asecond gear-changing and synchronization device associated with theadditional intermediate shaft which synchronizes and operativelyconnects the second gearwheel on the intermediate shaft to the secondgearwheel on the layshaft in order to transmit the electric-motor torqueof the electrical machine from the additional intermediate shaft to thetransmission output shaft.
 5. Vehicle according to claim 1, wherein therotor of the electrical machine is connected to a rotor holder, which isconnected in a rotationally fixed manner to a third gearwheel which isoperatively connected to a fourth gearwheel, which is connected in arotationally fixed manner to the additional intermediate shaft. 6.Vehicle according to claim 1, wherein a pair of gearwheels are arrangedsuch that they at least partially intersect in the axial direction inorder to transmit a torque between the electrical machine and theadditional intermediate shaft and the electrical machine.
 7. Vehicleaccording to claim 1, wherein the electrical machine is useable as astarter/generator when the first gearwheel on the additionalintermediate shaft interacts with the first gearwheel on the layshaft,and is useable as a further drive machine when the second gearwheel onthe additional intermediate shaft interacts with the second gearwheel onthe layshaft.
 8. A vehicle, comprising: a drive machine; a transmissionoperatively coupled to transmit torque from the drive machine, thetransmission having a transmission output shaft and a transmission inputshaft, the torque from the drive machine being transmittable to thetransmission output shaft; an electrical machine having a rotor and astator, said electrical machine producing an electric motor torqueoptionally connectable to the transmission input shaft or thetransmission output shaft, wherein the transmission is a manualtransmission, and wherein the manual transmission further comprises alay shaft and an intermediate shaft, first and second gear wheels beingarranged on the lay shaft so as to be operatively associated withcorresponding first and second gear wheels on the intermediate shaft,wherein one of said first and second gear wheels on the lay shaft beingoperatively coupled to a corresponding one of said first and second gearwheels on the intermediate shaft.
 9. The vehicle according to claim 8,wherein the intermediate shaft is connected to the rotor of theelectrical machine.
 10. The vehicle according to claim 8, furthercomprising a first gear-changing and synchronization device operativelyassociated with the intermediate shaft, said first gear-changing andsynchronization device operatively connecting the first gear wheel onthe intermediate shaft to the first gear wheel on the lay shaft in orderto transmit the electric-motor torque of the electrical machine from theintermediate shaft to the transmission input shaft.
 11. The vehicleaccording to claim 10, further comprising a second gear-changing andsynchronization device operatively associated with the intermediateshaft, said second gear-changing and synchronization device operativelyconnecting the second gear wheel of the intermediate shaft to the secondgear wheel of the lay shaft in order to transmit the electric-motortorque of the electrical machine from the intermediate shaft to thetransmission output shaft.
 12. The vehicle according to claim 8, furthercomprising a second gear-changing and synchronization device operativelyassociated with the intermediate shaft, said second gear-changing andsynchronization device operatively connecting the second gear wheel onthe intermediate shaft to the second gear wheel on the lay shaft inorder to transmit the electric-motor torque of the electrical machinefrom the intermediate shaft to the transmission output shaft.
 13. Thevehicle according to claim 8, further comprising a gear-changing andsynchronization device, wherein said electrical machine and saidgear-changing and synchronization device are arranged so as to intersectone another at least partially in an axial direction of thetransmission.
 14. The vehicle according to claim 13, wherein theelectrical machine is connectable via the gear-changing andsynchronization device at least to the transmission input shaft.
 15. Thevehicle according to claim 8, wherein the transmission is an automatictransmission, in which the electric motor torque from the electricalmachine is switchable backwards and forwards between the transmissioninput shaft and the transmission output shaft via epicyclic gearing. 16.The vehicle according to claim 8, further comprising a second electricalmachine, said second electrical machine transmitting an electric motortorque at least to an output shaft of the drive machine.